A co-pilot who hijacked his own plane in a bid to gain asylum threatened to crash the aircraft, a passenger has claimed.

The Ethiopian man, who has been named as Hailemedehin Abera Tagegn, seized control of the Boeing 767 when the Italian pilot went to the toilet.

Ethiopian Airlines flight ET702, with 202 passengers and crew on board, had taken off from the Ethiopia's capital, Addis Ababa, bound for Rome.

And passenger Francesco Cuomo told Italian news agency ANSA the pilot demanded the hijacker open the door and tried unsuccessfully to break it down.

He added the hijacker, speaking in poor English on a loudspeaker, threatened to crash the aircraft if the pilot persisted. The plane's oxygen masks then came down, Mr Cuomo said.

Video:Harriet Hadfield Reports In Geneva

Another passenger, Diego Carpelli, told Italian newspaper Corriere della Sera: "We had no clue about the hijacking but got scared when the plane suddenly started diving, it seemed like it was falling from the sky."

The co-pilot safely landed the plane in Geneva, Switzerland, at around 5am.

He used a rope to climb down from a cockpit window and surrendered to police on the runway. Officials earlier said passengers had not been aware of the hijack.

Redwan Hussein, Ethiopia's information minister, said the hijacker, who he named as Hailemedehin Abera Tagegn, had been working with the airline for five years and had no criminal record.

Mr Hussein described him as "medically sane", which he said made the motives for his actions all the more puzzling.

"So the intention, what forced him to hijack his own plane, still beggars belief ... any political, social or economic reason would not make sense to hijack your plane and be a criminal," he said.

Police spokesman Pierre Grangean said: "Just after landing, the co-pilot came out of the cockpit and ran to the police and said, 'I'm the hijacker.' He said he is not safe in his own country and wants asylum."

Swiss federal authorities are now investigating and could press charges that could carry a prison sentence of up to 20 years. In Ethiopia, he could face up to 25 years in jail.

FlightRadar 24 - an app for mobile devices - showed the flight circling over Geneva several times before landing.

The Boeing 767-300 plane had 20 minutes of fuel left when it landed after being guided to the runway by two Italian fighter planes.

Sky's Harriet Hadfield, in Geneva, said the airport had not yet opened when the plane hit the runway - and passengers had to wait until it did before disembarking.

Speaking about why the co-pilot might have been seeking asylum, Human Rights Watch said Ethiopia's human rights record "has sharply deteriorated" over the years.